Hybrid and electric vehicles pose
electric/magnetic isolation challenges
Frank Forster, Texas Instruments
10/14/2010 9:28 PM EDT
Hybrid and electric vehicles (HEV/EVs) introduce voltages of 400V and higher.
Operating with such high voltages and currents in the harsh automotive environment drives the need for highly robust but also long term stable solutions for isolating these high levels from the other electronic functions—and most importantly from the passengers.
Hybrid and electric drivetrains in cars, trucks, and two-wheelers are introducing new, previously unknown challenges in the transportation design.
The 12V board net is now complemented with a 400V or higher battery and power system, which introduces a completely new set of requirements for automotive OEMs and system module providers.
An isolation need is present in all functions of the HEV/EV powertrain, such as the battery, DC/DC converter, and inverter for driving the electric motor, but also for the charger module connected to the 230V/380V power grid.
Isolation in automotive and transportation applications introduces different requirements compared to the industrial space. And it also has to be very robust against magnetic ‘noise’. The high power levels in vehicles (e.g. a 100kW electric engine operating at 400V means currents of 250A) will create strong magnetic fields in the car that have to be handled. But also a long lifetime of components meeting the vehicle life expectancy (that can reach several decades in the heavy transportation space) has to be ensured. Use in the automotive environment will drive the need for automotive qualification (Q1) and an operating temperature range of -40 to +125C.
At the same time, cost pressure in these areas will drive the need for higher system level integration, so a product roadmap with single-chip, isolated functions like CAN transceivers, ADCs, or gate drivers is of advantage.
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